1. Field of the Invention
The present invention relates to an information storage medium, and more particularly, to an information storage medium which stores information about an optimal writing pattern or information about whether the information storage medium is compatible with a drive following an older version of standards.
2. Description of the Related Art
General information storage media are widely used as information recording media of optical pickup apparatuses for recording/reproducing information in a non-contact way. Optical disks, which are an example of information storage media, are classified as compact disks (CDs) or digital versatile disks (DVDs) according to their information storage capacity. Examples of recordable optical disks include 650 MB CD-R, CD-RW, 4.7 GB DVD/RW, DVD-RAM, and the like. Furthermore, HD-DVDs having a recording capacity of 20 GB or greater are under development.
With the increase in the recording capacity of optical disks, the recording speed thereof has also developed. However, the recording pattern of optical disks changes as the recording speed thereof increases.
FIG. 1A shows a writing pulse pattern widely used in CD-RW, DVD-RAM/R/RW, and the like. The writing pulse pattern of FIG. 1A includes multiple pulses to form each mark on the optical disk. The multi-pulse pattern is widely used to prevent distortion of the marks on the optical disk due to heat accumulation during mark formation. However, because the energy provided per unit time decreases with an increase in the recording speed of optical disks, an error may be generated when data is recorded according to the multi-pulse pattern.
However, the reduction in the energy per unit time can be compensated for by using a single pulse for each mark, as shown in FIG. 1B, or by increasing bias power.
As described above, information storage media have different writing patterns, that is, writing strategies, according to their recording speeds. FIG. 2 shows a data area structure of a conventional information storage medium. As shown in FIG. 2, a conventional information storage medium includes a lead-in area 100, a user data area 110, and a lead-out area 120. Information about a data writing pattern is recorded in a disk control data zone 100-2 of the lead-in area 100.
The lead-in area 100 includes a first buffer zone 100-1, the disk control data zone 100-2, in which disk control-related information is recorded, a disk test zone 100-3, a drive test zone 100-4, a defect management zone 100-5, a reserved zone 100-6, and a second buffer zone 100-7. The disk control data zone 100-2 stores the disk-type, the disk version number, the disk size, information about a recording layer(s), and the like. The disk control data zone 100-2 also stores the information about the data writing pattern.
For example, the disk control data zone 100-2 may store information concerning first through third writing pattern types. The first writing pattern type can be a first multi-pulse pattern, the second writing pattern type can be a second multi-pulse pattern, and the third writing pattern type can be a single-pulse pattern. In FIGS. 1A and 1B, Ttop, Tmp, and Tcl are parameters of a writing pattern, namely, initial pulse time, multi-pulse time, and cooling pulse time, respectively. Pw, Pe, and Pb denote writing power, erasing power, and bias power, respectively. T denotes the minimum length of a recording mark. 3T and 7T denote the lengths of a mark or space.
For example, fifth through ninth bytes of the disk control data zone 100-2 store a first recording speed, a first reproduction power, Ttop1, Tmp1, and Tcl1, respectively, as the information about the first writing pattern type. A tenth byte of the disk control data zone 100-2 is reserved. Eleventh through fifteenth bytes of the disk control data zone 100-2 store a second recording speed, a second reproduction power, Ttop2, Tmp2, and Tcl2, respectively, as the information about the second writing pattern type. A sixteenth byte of the disk control data zone 100-2 is reserved. Seventeenth through twenty-first bytes of the disk control data zone 100-2 store a third recording speed, a third reproduction power, Ttop3, Tmp3, and Tcl3, respectively, as the information about the third writing pattern type. A twenty-second byte of the disk control data zone 100-2 is reserved.
As described above, the conventional information storage medium classifies the information about writing patterns according to the writing pattern type and stores the information. If information about several writing patterns has been recorded, when a drive records data in an information storage medium, it reads out the information about all of the writing patterns, selects a writing pattern suitable for the drive itself, and records data according to the selected writing pattern. In other words, after the information storage medium of FIG. 2 is loaded in the drive, the drive must test all of the first through third writing pattern types to find an optimal writing pattern. Consequently, the drive must be designed so as to include a function of testing writing patterns, thus complicating a drive design and increasing the duration of recording data.
In the conventional information storage medium of FIG. 2, information about its recording speed is recorded in the disk control data zone 100-2. Information about the version of the information storage medium, which prescribes a standard for the recording speed, is also recorded in the disk control data zone 100-2. When such a disk is loaded in a drive to record/reproduce data on/from the disk, the drive first reads out the information about the version of the loaded disk. If the version of the loaded disk is identical to the version of the drive, the drive records/reproduces data on/from the loaded disk.
However, when a new version of an information storage medium is developed, a drive corresponding to the new version must also be developed. A drive following an older version of standards cannot record/reproduce data on/from the information storage medium following the new version of standards. In other words, when an information storage medium is loaded in a drive, the drive reads the version information stored in the information storage medium and can record/reproduce data on/from the information storage medium only if their versions are identical. On the other hand, if the version of the loaded information storage medium is different from that of the drive on which the information storage medium is loaded, the drive cannot recognize the loaded information storage medium because the information storage medium stores version information different from the information about the version of the drive.
Accordingly, regardless of whether a drive is compatible with an information storage medium following a different version of standards, the drive automatically recognizes that it cannot record/reproduce data on/from the information storage medium following a different version of standards.
As described above, if an information storage medium following a new version of standards stores no information about a drive following an older version of standards, the new version of information storage medium cannot be used in the drive following an older version of standards, even if they are really compatible with one another. Hence, users suffer the inconvenience and expenses of having to use new drives whenever the newer version of an information storage medium is used.